Semiconductor diodes are two-terminal electronic components – a diode containing a “PN junction” made from differently doped semiconductor materials. A depletion area arises at this connection, with no holes or electrons. A positive anode voltage reduces the depletion region, allowing current to flow; a negative anode voltage increases the depletion region, blocking current flow.
Read More – Semiconductor Diode
Important Questions with Answers
1. Why are semiconductor diodes non-ohmic?
The electrical conductors which do not follow Ohm’s law are called non-ohmic conductors. The semiconductor diodes are non-ohmic because the voltage drop in the diode is constant even if the current is varied. Hence, there is no linear relationship between the current and voltage.
2. How does a semiconductor diode work?
Semiconductor diodes operate due to an imbalance of electrons. This electron imbalance generates positive (where there are surplus protons) and negative (where there are excess electrons) charges at the two ends of the semiconductor material’s surfaces. This is how a semiconductor operates.
3. What is p-type and n-type semiconductor?
In a P-type semiconductor, trivalent impurities of group III such as Aluminium, Indium and Gallium are added as the impurities. The trivalent impurities are added to provide extra holes
In an n-type semiconductor, pentavalent impurity from the V group is added to the pure semiconductor. Examples of pentavalent impurities are Arsenic, Antimony, Bismuth etc. The pentavalent impurities provide extra electrons and are termed donor atoms. Electrons are the majority of charge carriers in n-type semiconductors.
4. What are the two types of semiconductors?
The two types of semiconductors are:
Intrinsic Semiconductor
Extrinsic Semiconductor
5. Semiconductor diodes can be used as a _______.
- oscillator
- amplifier
- rectifier
- modulator
Answer: c. rectifier
Explanation: Semiconductor diodes can be used as a rectifier. A rectifier’s job is to convert alternating current to direct current by allowing current to flow in just one direction.
6. What are the uses of semiconductor diodes?
Semiconductor diodes have a wide range of applications, which includes the following:
- Semiconductor diodes in logic gates: These are utilised to execute logic operations. Small and big logic gate states are analogous to forward and reverse bias semiconductor diode states. As a result, diodes are useful in OR, NAND, and AND gates.
- Semiconductor rectifier: These diodes are commonly used to convert alternating current to direct current.
- Semiconductor diode in clamping circuit: These convert a negative input signal to a positive signal or vice versa.
- Semiconductor diode in a clipping circuit: These are commonly seen in FM transmitters. LED gadgets make use of semiconductor diodes. The primary goal is to emit infrared light. Zener diodes are used in the stabiliser. It primarily stops the overflow of current.
7. Who made the first semiconductor diode?
- Ferdinand Braun
- Sir Issac Newton
- Georg Simon Ohm
- John Ambrose Fleming
Answer: a. Ferdinand Braun
Explanation – Semiconductor diodes were the first semiconductor electronic devices. German physicist Ferdinand Braun made the discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal in 1874.
8. What are the types of semiconductor diodes?
Following are the types of semiconductor diodes:
- LED
- Zener diode
- Rectifier diode
- Tunnel diode
- Variable capacitance diode
- Photodiode
9. Who discovered the PN junction?
- Physicist Ferdinand Braun
- Sir Issac Newton
- Georg Simon Ohm
- Russell Ohl
Answer: d. Russell Ohl
Explanation – Russell Ohl finds the PN junction and photovoltaic properties in silicon that lead to the invention of junction transistors and solar cells. Russell Ohl, an electrochemist at Bell Telephone Labs in Holmdel, NJ, began researching the use of silicon rectifiers as radar detectors in the mid-1930s.
10. What happens when applying a forward bias to a PN junction diode?
When a forward bias is applied to a PN junction diode, the value of the potential barrier decreases. The potential barrier opposes the applied voltage in the case of a forward bias. As a result, the potential barrier across the junction decreases.
Practice Questions
- What is a semiconductor diode?
- What is the symbol of a junction?
- What happens when applying a reverse bias to a PN junction diode?
- Explain the characteristics of semiconductor diodes.
- A rectifier diode is used for the rectification of alternating current.
- True
- False
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